For the server.class server to run, it must be saved to a server computer with a Java Virtual Machine. Ideally, the server servlet would be placed in the same folder as the digitiser and viewer applets. Before running the servlet, a subdirectory named 'temp' must be created to hold the data files.
To run the server, type:
mark@my_server$ java ./server
at the prompt. The servlet runs on port 4444 by default, but allowing this to be set at start up would be quite simple.
When the server recieves a connection from the digitiser applet, they do a small handshake and confirm that they are both who they should be, and then the applet streams the digitised data back to it, for the servlet to save locally.
This data may now be encorporated into the viewer applet by ammending the viewer applets parameter tag.